Abstract
With relation to thermionic power conversion, thermionic emission measurements have been carried out on carbide-coated tungsten filaments in the temperature range of 1, 400°2, 100°K. Carbide coating was done by electrophoresis in n-butyl alcohol suspending carbide powder. From the Shottky plots for d.c. field as high as 6·106 V/m, thermionic saturation currents were estimated. Richardson plots showed that Richardson constant A and work function φ was 160 A/cm2·deg2, 3.8 V for UC; 420 A/cm2·deg2, 4.2 V for U0.5Zr0.5C; and 360 A/cm2·deg2, 4.2 V for ZrC, respectively. The result for ZrC rather agreed with the result by Pidd, et al., but an abnormally large A value which Pidd, et al., had obtained for UC and (U, Zr) C was not observed from our measurements. Thermionic characteristics of UC was seemed to be complex.
